In general, in transmission modules used for a phased array antenna apparatus, means for controlling the phases of output signals of the transmission modules is required for highly efficient operation in order to achieve a reduction in the power consumption of a high frequency amplifier (high output amplifier) within each transmission module, as well as in order to change the directivity of an antenna. In addition, in order to carry out beam forming, it is necessary to suppress an amplitude error and a phase error between the transmission modules connected to individual element antennas of the phased array antenna, respectively.
In the past, transmission modules used for a phased array antenna apparatus are constructed such that they are each provided with a high frequency amplifier and a phase shifter, so that the phases of the individual transmission modules are controlled in order to amplify a signal by means of the high frequency amplifier and to carry out beam forming by means of a phase shifter (for example, refer to a first patent document).
In addition, in the past, in a phased array antenna apparatus which uses a plurality of transmission modules, there has been proposed a method in which when a phased array antenna is formed by the use of transmission modules of the same output power, not only the phase but also the amplitude thereof can be controlled so as to obtain a sufficient directional gain and at the same time to reduce a side lobe level by thinning out element antennas so as to provide an amplitude distribution (for example, refer to a first nonpatent document).
Further, in a phased array antenna apparatus described in the first nonpatent document, in order to improve accuracy as well as to reduce the electric power consumption of the phased array antenna apparatus, a plurality of transmission modules, which are different in saturated output electric power from one another, are prepared, and the thinning out of antennas and combination of the antennas are carried out.
In this case, when a phased array antenna is formed by the use of transmission modules of the same saturated output electric power, element antennas are thinned out to provide an appropriate amplitude distribution, whereby not only the phase but also the amplitude thereof can be controlled so as to achieve that a sufficient directional gain is obtained or a side lobe level is reduced.
In addition, by preparing a plurality of transmission modules which are different in saturated output electric power from one another, and by combining this with the thinning out of the antennas thereby to provide an amplitude distribution, the electric power consumption of the antenna apparatus is reduced.